Active Steering Assist is only available up to a speed of 210 km/h. The system helps you to stay in the centre of the lane by means of moderate steering interventions. Depending on the speed driven, Active Steering Assist uses the vehicles ahead and lane markings as a reference.
Depending on the country, in the lower speed range Active Steering Assist can use the surrounding traffic as a reference. If necessary, Active Steering Assist can then also provide assistance when driving outside the centre of the lane, for example to form a rescue lane.
If the detection of lane markings and vehicles ahead is impaired, Active Steering Assist switches to passive mode. The system provides no support in this case.
(grey): activated and passive - (green): activated and active
- (red): system limits detected
- (white, red hands): "hands on the steering wheel" prompt
During the transition from active to passive status, the symbol is shown as enlarged and flashing. Once the system is passive, the symbol is shown as grey in the multifunction display.
Depending on the selected vehicle settings, Active Steering Assist may be unavailable.
The driver is required to keep their hands on the steering wheel at all times and be able to intervene at any time to correct the course of the vehicle and keep it in lane. The driver must expect a change from active to passive mode or vice versa at any time.
If the system detects that the driver has not steered the vehicle for a considerable period of time or has removed their hands from the steering wheel, display 
appears. If the driver still does not steer the vehicle, a warning tone sounds in addition to the visual warning message.
If the driver does not react to this warning for a considerable period, an emergency stop is initiated More.
The driver steers the vehicle.
Depending on the country: the driver presses a steering wheel button or operates Touch Control
If Active Steering Assist detects that a system limit has been reached, a visual warning is issued and a warning tone sounds.
Observe the notes on driving systems and your responsibility; you may otherwise fail to recognise dangers More.
Active Steering Assist has a limited steering torque for lateral guidance. In some cases, the steering intervention is not sufficient to keep the vehicle in the lane or to drive through exits.
There is poor visibility, e.g. due to snow, rain, fog, heavy spray, greatly varying light conditions or strong shadows on the carriageway.
There is glare, e.g. from oncoming traffic, direct sunlight or reflections.
Insufficient road illumination.
The windscreen is dirty, misted up, damaged or covered in the vicinity of the camera, e.g. by a sticker.
No, or several, unclear lane markings are present for one lane, or the markings change quickly, for example, in a construction area or junctions.
The lane markings are worn away, dark or covered up, e.g. by dirt or snow.
If the distance to the vehicle in front is too short and thus the lane markings cannot be detected.
The road is narrow and winding.
There are obstacles on the lane or projecting out into the lane, such as object markers.
On tight bends and when turning.
When crossing junctions.
At roundabouts or toll stations.
When towing a trailer.
When the tyre pressure is too low.
If the system limits of Active Steering Assist are reached there is no guarantee that the system will remain active or will keep the vehicle in lane.
The detection of lane markings and objects may malfunction and cause unexpected steering interventions.